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2 Sheets-Sheet 1. E. T. GILLII XND.

Electrical Swito Board.

fF2tented Aug. 24,1880;

WITNESSES.

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E. T. GILLILAND.

Electrical Switch Board.

No. 231,421. Patented Aug. 24,1880.

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N PETERS, FHOTO-LITHQGRAPHER. WASHINGTUNV D 0.

UNITED STATES PATENT OFFICE.

EZRA T. GILLILAND, CF INDIANAPOLIS, INDIANA, ASSIGNOR TO THE GILLI- LAND ELECTRIC MANUFACTURING COMPANY, OF SABIE PLACE.

ELECTRICAL SWITCH-BOARD.

SPECIFICATION forming part of Letters Patent No. 231,421, dated August 24, 1880.

Application filed November 24, 1879.

To all whom it may concern Be it known that I, EZRA T. GILLILAND, of the city of Indianapolis, county of Marion, and State of Indiana, have invented certain new and useful Improvements in Electrical Switch- Boards, of which the following is a specification.

Reference is had to the accompanying drawings, which are made a part hereof, and on which similar letters of reference indicate similar parts.

Figure 1 is a front elevation of a section of my improved board. Fig. 2 is a transverse vertical section thereof on the dotted line a x.

Fig. 3 is a transverse horizontal section on the dotted line 22. Figs. 4 and 5 are side and edge views, respectively, of the plug. Fig. 6 is a plan of a larger section of board than Fig. 1, though on a smaller scale, but showing the mode of grouping the strips more clearly.

In said drawings, the portion marked A represents the wooden board employed as a foundation-piece to support the metal parts of the device; 13, rails attached to said board,

2 5 which enable said board to support both sets of metal strips without allowing them to come in contact with each other 5 C, metal strips, usually known in this connection as connection-strips D, metal strips, usually known as 0 line-stripsfl and E, a device electrically connecting any of said connection-strips to any of said linestrips, and usually known as a switch-plug.

My invention consists in the peculiar con- 3 5 struction and arrangement of the several parts of which the device is composed, and the object is to render said device cheaper and more efficient than such switch-boards usually are.

The strips C are formed to project outwardly at intervals from the face of the board A, when applied thereto, in such form that the faces of the projecting parts shall be at about right angles with the face of the board. The strips D are set edgewise in the rails B, and run directly 5 across said strips C, but not in contact with them. The proj ectin g parts of the strips C come to nearly or quite the level of the outer edges of the strips D, and thus interstices are formed between said strips, into which the plugs E may be inserted.

As all the line-strips cross all the connection-strips, any line may, at pleasure, be con nected with any other line by so inserting plugs as to connect both the line'strips representing such lines with one connection-strip.

In telephone-exchanges one or more of the strips C on each board are usually used as in strument-strips, so that any line may be connected with the central office by properly in serting a single plug.

In order that the plugs shall not come in contact by reason of hasty use, and thus confuse the electrical operation, corrugations or small projections d d are formed at the proper points on the strips D, between which the plugs are inserted, and are thus always brought to and kept in their proper position.

I prefer to make the strips C and D of sheet metal and bend them to the form required; but pieces cast or forged so as to occupy the 0 same relative positions to each other when placed upon the board would be equally within the scope of my invention. The plugs E are also made of a peculiar construction. To the handle E, which is made, as ordinarily, ot'some insulating material, are riveted two springstrips, 0 a. They are thus constructed very much cheaper, have more elasticity, will wear longer, and are less liable to have a shoulder worn thereon than are the round plugsiu tele- 8o graphicswitch-boards, which are the only analogous plugs of which I have any knowledge.

Electrical switch-boards for telegraphic purposes have heretofore been usually constructed with a series of parallel strips, in the adjacent edges of which are cut semicircular indenta tions, which in the strips intended to be connected are placed opposite to each other. Round plugs, turned to fit the openings made by these indentations, and with their ends 0 slitted to give a slight spring or elasticity, have been used to make the connections.

The disadvantages of this style of board are that it is very expensive, in that it takes accurate and laborious workmanship to properly construct it; that it is liable to get out of order and become useless, in that the board may warp, and thus disarrange the relation of the indentations, so that the plug will not fit, and also in that the plugs are liable to havea 10o shoulder worn on them by frequent use, so that they will not fit tightly even when the board is in order.

Electrical switch-boards for telephonic purposes have been used in which the construction was substantially one set of strips having holes therein and connected by flexible electrical cords having plugs upon the ends, and which correspond to the connection-strips in my invention.

The disadvantages of this style are that in making a large number of connections the cords are liable to get interwoven and tangled, and are rapidly worn out, and therefore expensive.

It will be readily seen by an examination of my drawings and the foregoing description and explanation, that I avoid these disadvantages entirely, and at no expense of efificiency.

Besides avoiding the disadvantages named in the construction of my board, I have increased its efficiency by an arrangement of the strips which makes it possible for the operator to use it much more rapidly than could otherwise be done.

It has heretofore required a comparatively slow and careful following of the line of the strips across the board in order to be sure and make the required connection. By arranging the strips in groups-that is, leaving a wider space between the strips at certain intervals than between the intermediate strips-or by interposing wooden rails at similar intervals, or both, the line can be followed much more rapidly, and consequently the operator can make the required connection in much less time than would otherwise be possible.

The exact form of groups which I have adopted as one well suited to my purpose is shown in the drawings, Fig. 6. The'connection-strips are shown as divided into groups of five by the wooden rails B, while the linestrips are shown as divided into groups of ten by a wider space being left between each ten upon the board. In following the connectionstrips (which are the ones which nearly always have to be followed) the operator, out of the five strips in the group, has only to notice that the first plug is inserted in connection with the top, bottom, central, next to top, or next to bottom strip, and keep that fact in mind, paying no further attention to the board until he reaches the place where the other plug is to be inserted. If the plugs are to be inserted several feet apart, the proportion of time gained by employing this simple arrangement is very great, less operators are needed, and greater efficiency secured.

The strips in the group of two and the single one are not used as connection-strips, but are for purposes peculiar to telephone exchanges, for use in which my invention is principally designed, though, except as to the grouping, its advantages are as marked when used for telegraphic purposes.

Having thus fully described my said invention, what I claim as new, and desire to secure by Letters Patent, is

1. An electrical switch-hoard consisting of two sets or series of insulated bars or strips, the bars of one set being looped or corrugated and those of the other set being arranged alongside the projections formed by the loops or corrugations of the first, thus producing interstices between the several bars or strips of the two sets in which to insert the switchplug, substantially as herein set forth.

2. In an electrical switch-board, one of the sets of conducting-strips formed with loops or outwardly-projecting parts, which rise alongside and near to the other set, which is set in edgewise relative position to the first set, substantially as and for the purposes set forth.

3. In an electrical switch-board, one of the sets of conductingstrips formed with corrugations or small projections upon their faces, when said set of strips are set in edgewise relative position to the other set, for the pura pose of guiding the plug to its proper position, substantially as shown and specified.

4. The combination, in an electrical switchboard, of the strips 0 and D and plug E, constructed, arranged, and operating substantially as set forth.

5. The switch plug E, composed of the handle E and springs c c, all constructed as shown, and operating substantially as and for the purpose specified.

6. In an electrical switch-board, the rails B, for the purposes of supporting one set of the conducting-strips and of dividing the other set into groups, substantially as herein set forth.

In witness whereof I have hereunto set my hand and "seal, at Indianapolis, Indiana, this 20th day of November, A. D. 1879.

EZRA T. GILLILAND.

In presence of-- A. B. GILLETT, O. BRADFORD. 

